This gist contains boiler plate code which you can copy paste evertime you want to do the given operations

BoilerPlateAndroidSnippets

Getting server data :


public class AsyncgetTopics extends AsyncTask<String,Void,String> {


        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            bar.setVisibility(View.VISIBLE);
          //pd= ProgressDialog.show(Activity.this,"Getting data","Please wait..",true,false);
        }

        @Override
        protected String doInBackground(String... params ) {

            String result ="";
            int status = 0;
            String downloadurl=getResources().getString(R.string.BASE_URL)+"/route";

            try{

                URL url=new URL(downloadurl);
                try{
                    HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
                    String postParameters=
                            "param0="+params[0]
                            +"&param1="+params[1];

//                    USING POST HERE
//                    To use GET ,change the url appropriately and add params directly there.
                  

                    urlConnection.setRequestMethod("POST");
                    urlConnection.setRequestProperty("Content-Type",
                            "application/x-www-form-urlencoded");
                    urlConnection.setFixedLengthStreamingMode(
                            postParameters.getBytes().length);
                    PrintWriter out = new PrintWriter(urlConnection.getOutputStream());
                    out.print(postParameters);
                    out.close();

                    InputStream inputStream=urlConnection.getInputStream();
                    status=urlConnection.getResponseCode();
                    BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream));

                    String line="";
                    while((line=bufferedReader.readLine())!=null){
                        Log.d("line",line);
                        result+=line;
                    }
                    try {
                        JSONObject object=new JSONObject(result);
                        JSONArray array=object.getJSONArray("topics");
                        for(int i=0;i<array.length();i++){
                            topicList.add(array.getString(i));
                            Log.d("list",array.getString(i));
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                    Log.d("DATA",result);
                    inputStream.close();




                } catch (IOException e) {
                    e.printStackTrace();
                }


            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            //return topiclist;
            return String.valueOf( status);
        }


        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);

           
            bar.setVisibility(View.GONE);
          //pd.dismiss();
        }
    }

   
Setting up viewPager :
    
    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
        adapter.addFragment(Frag.newInstance("something"), "Tab1");
        adapter.addFragment(Frag.newInstance("somethingelse"), "Tab2");
        viewPager.setAdapter(adapter);
    }
    class ViewPagerAdapter extends FragmentPagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();

        public ViewPagerAdapter(FragmentManager manager) {
            super(manager);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

        @Override
        public int getCount() {
            return mFragmentList.size();
        }

        public void addFragment(Fragment fragment, String title) {

            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return mFragmentTitleList.get(position);
        }
    }
    
    
SharedPreferences:

onCreate(){
        SharedPreferences prefs = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
}
public void save(Context context, String key, String value) {
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(key, value);
        editor.commit();
 }
 public void get(String key, String defaultValue){
        sharedPreferences=getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
        String picurl=sharedPreferences.getString(key,defaultValue);
 }